The poultry and livestock industry is rapidly adopting the confined, environment controlled, isolated unit approach for the managing and raising of poultry and livestock. This approach, wherein the poultry or livestock is continuously confined within a building, is desirable from the standpoint of providing improved working conditions for the caretaker of the animals, and at the same time is also believed to result in greater growth or productivity. However, confinement of the animals has also produced or assisted in the development of disease conditions which were seldom seen previously. Further, improper ventilation can result in accumulation of excessive moisture which encourgages the proliferation or build-up of disease producing bacterial organisms. Thus, under confined conditions, the maintaining of acceptable air temperature, humidity, ventilation and air purity is essential if the animals are to remain healthy and are to have maximum growth or productivity.
The maintaining of proper environmental conditions within the confinement is particularly critical for animals such as swine. For growing swine, the optimum air temperature is normally 50.degree.-60.degree. F, since at these temperatures the swine will use little feed to keep warm and will usually want to eat at a high rate, thereby resulting in maximum weight gain. However, at higher temperatures, swine do not eat as much feed, and do not gain as rapidly. On the other hand, at lower temperatures, some of the feed nutrients must be used to produce body heat and therefore weight gain is reduced. Thus, the control of confinement temperature is essential in order to result in optimum growth of the swine.
Further, control over humidity in the confinement is also essential and critical since the humidity should be between 50 and 80 percent in order to provide for optimum health of the swine. Both high and low humidities may cause respiratory problems which severely effect the swine, particularly since swine are susceptible to flu and similar diseases during the fall and spring seasons. The control over the humidity within the confinement, and the continual and rapid changing of air within the confinement, is thus essential if the spreading of respiratory diseases such as flu are to be avoided.
In an attempt to provide a controlled environment within a livestock confinement, various systems have been devised. Most of these systems have utilized fans either for forcing air into the confinement or for removing air from the confinement. However, the overall arrangement of these known systems has not resulted in close control over the environment within the confinement, since these systems have not permitted a large number of air changes to be made within the confinement, nor have these systems permitted air changes to be made without resulting in excessive drafts or temperature changes within the confinement.
Accordingly, it is an object of the present invention to provide an improved ventilation system for use with a livestock confinement for permitting precise control over the environment within the confinement. In particular, it is an object of the present invention to provide an improved ventilation system which permits precise control over the confinement temperature and also permits a large number of air changes to be made per unit of time so as to control both air purity and humidity, which air changes can be made in a manner which minimizes the intake air velocity to thus substantially eliminate drafts within the confinement.
A further object of the present invention is the provision of an improved ventilation system which maintains a preselected pressure differential between the confinement pressure and the atmospheric pressure, with the intake ventilation system being automatically and variably controlled in response to the variation of the confinement pressure from a preselected level so as to permit controlled amounts of air to be supplied to the confinement.
Other objects and purposes of the present invention will be apparent to persons acquainted with structures of this general type upon reading the following specification and inspecting the accompanying drawings.